This application relates to a method of reducing power consumption of a semiconductor device, and more particularly, to a method of reducing power consumption caused by leakage current in an interface circuit between modules that are driven by different power sources.
As much attention has been paid to systems having various functions and system portability, a major concern in system design is to develop multi-functional and low power systems. Systems, such as portable terminals, which use a battery with a limited amount of power enter a sleep mode except during normal (i.e., non-sleep mode) operation, thereby reducing consumption of the battery power. In certain situations, a signal input to a terminal may be a logic high ‘1’ or logic low ‘0’, and the system operates accordingly. However, if a system cannot determine whether a signal input via a particular terminal included in a system is logic high ‘1’ or logic low ‘0’, then the system may malfunction or there might be unnecessary power consumption. That is, if the level of the input signal approximates a logic threshold voltage that is unknown as to whether it corresponds to logic ‘high’‘1’ or logic ‘low’‘0’, then a current path may be formed between a power supply voltage source and a ground voltage source. As such, static current, i.e., leakage current, may flow between the power voltage source and the ground voltage source, thereby causing unnecessary power consumption. In particular, it is important to prevent generation of the leakage current in order to reduce power consumption in a semiconductor integrated circuit that uses a MOS transistor. Whether the leakage current can be prevented is closely related to the competitiveness of products, such as portable terminals, the power saving capability of which is considered as a major advantageous factor.